Histological quantification of the tissue damage caused by PlasmaJet™ coagulator

The purpose of this study was to evaluate tissue damage caused by the PlasmaJet^TM coagulator in the uterus, ovary, and fallopian tube at different power settings in vitro and then to examine the damage caused in vivo. In vitro evaluation included prospective recruitment of six subjects undergoing hysterectomy with or without salpingo-oophorectomy. Tissue damage was evaluated histologically for power levels at 10%, 15%, and 20%, and for duration of 2 and 5 s at a clinically acceptable distance of 0.5 to 1 cm between the tip of probe and tissue. In vivo evaluation included 15 subjects undergoing hysterectomy with or without salpingo-oophorectomy. The most suitable power setting and duration of diathermy was decided from in vitro examination and applied on in vivo setting. Tissue damage was evaluated histologically. There was no significant difference seen in the depth and width of tissue damage in the in vitro specimens at different low power levels and duration of diathermy (P > 0.05). A setting of 20% power and duration of 5 s of diathermy was used therefore for in vivo setting. Mean ± SD depth (millimetres) of tissue damage in uterus, ovary, and fallopian tube were 0.63 ± 0.19, 0.61 ± 0.14, and 0.63 ± 0.18, respectively. Mean ± SD width (millimetres) of tissue damage in uterus, ovary, and fallopian tube were 4.66 ± 0.05, 4.05 ± 0.61, and 4.51 ± 0.77, respectively. Irrespective of tissue type, the average depth and width of tissue damage with application of Plasmajet^TM coagulator for 5 s at low power is 0.62 and 4.24 mm, respectively. It therefore appears to be a safe method of coagulation in vitro and in vivo at 20% power on gynaecological tissues.     

Nationwide study of haemolytic uraemic syndrome: clinical, microbiological, and epidemiological features.

AIMS: To establish the incidence and aetiology of haemolytic uraemic syndrome (HUS) in Australia and compare clinical and microbial characteristics of sporadic and outbreak cases. METHODS: National active surveillance through the Australian Paediatric Surveillance Unit with monthly case notification from paediatricians, July 1994 to June 1998. Children under 15 years presenting with microangiopathic haemolytic anaemia, thrombocytopenia, and acute renal impairment were identified. RESULTS: Ninety eight cases were identified (incidence 0.64 per 10(5) children <15 years/annum and 1.35 per 10(5) children <5 years/annum). Eighty four were associated with diarrhoea (64 sporadic, 20 constituting an outbreak) and 14 were atypical. Shiga toxin producing Escherichia coli (STEC) O111:H- was the most common isolate in sporadic HUS and caused the outbreak. However O111:H- isolates from outbreak and sporadic cases differed in phage type and subtyping by DNA electrophoresis. STEC isolates from sporadic cases included O26:H-, O113:H21, O130:H11, OR:H9, O157:H-, ONT:H7, and ONT:H-. STEC O157:H7 was not isolated from any case. Only O111:H- isolates produced both Shiga toxins 1 and 2 and possessed genes encoding E coli attaching and effacing gene (intimin) and enterohemolysin. Outbreak cases had worse gastrointestinal and renal disease at presentation and more extrarenal complications. CONCLUSIONS: Linking national surveillance with a specialised laboratory service allowed estimation of HUS incidence and provided information on its aetiology. In contrast to North America, Japan, and the British Isles, STEC O157:H7 is rare in Australia; however, non-O157:H7 STEC cause severe disease including outbreaks. Disease severity in outbreak cases may relate to yet unidentified virulence factors of the O111:H- strain isolated.     

Nucleus basalis lesions attenuate aquisition,but not retention,of Pavlovian heart rate conditioning and have no effect on eyeblink conditioning

Summary Rabbits with lesions of the anterior nucleus basalis of Meynert (nBM) were compared with animals with sham lesions or unoperated control animals on a classical conditioning task in which heart rate (HR) and eyeblink (EB) conditioned responses (CRs) were as sessed. The nBM lesions impaired the magnitude of the decelerative HR CR, but had no effect on the EB CR. A second experiment, in which animals were lesioned af ter acquisition was complete, showed that anterior nBM lesions had no effect on retention of either the HR or EB CR. These data suggest that the anterior nBM may participate in the early stages of information processing in which stimuli are evaluated for their significance based on their association with a reinforcer. However, the ante rior nBM is apparently not involved in the selection of a somatomotor response to deal effectively with such changing stimulus contingencies.     

Cytogenetics of primary prostatic adenocarcinoma. Clonality and chromosome instability.

We have examined 62 prostatic adenocarcinomas by conventional cytogenetic analysis. Most were primary cultures harvested in 14 days or less. The most consistent finding was a normal male diploid karyotype, found in 87% of all cells analyzed, and as the exclusive finding in 19 tumors. Nonrandom chromosomal changes included gain of chromosome 7 and loss of the Y chromosome. In addition, clonal gains of chromosomes 8, 12, and 18, and clonal losses of chromosomes 14 and 19 were noted in individual cases. Two structural clonal aberrations, a 9p+ in one case and a t(Y;22) (q11.2;p12) in another, were also seen. Ten of 62 cultures demonstrated chromosome instability, defined herein as nonclonal gain or loss of chromosomes in more than 10% of the metaphases examined from that culture. In those cases with nonclonal numerical aberrations, loss of chromosomes was more common than gain. The distribution of apparently random numeric abnormalities was similar to that of the clonal abnormalities in that the most frequent nonclonal gain was of chromosome 7 and the most frequent nonclonal loss was of the Y chromosome. Apparently random structural aberrations were observed in less than 1% of all analyzed cells. These included a 4p-,del(3)(q13), and t(1;11). The extent of apparently random aneuploidy suggests that chromosome instability characterizes cultured prostatic adenocarcinomas. An increase in the frequency of nonclonal aberrations may be an indicator of tumor origin in a predominantly diploid cell population. The coexistence of clonally aberrant, nonclonally aberrant, and normal diploid cells in culture may reflect heterogeneity of prostate tumors in vivo.     

Ultrastructural and morphometric analysis of long-term peripheral nerve regeneration through silicone tubes

Summary Light and electron microscopy were used to investigate long-term regeneration in peripheral nerves regenerating across a 10 mm gap through silicone tubes. Schwann cells and axons co-migrated behind an advancing front of fibroblasts, bridging the 10 mm gap between 28 and 35 days following nerve transection. Myelination of regenerated fibres started between 14 and 21 days after transection and occurred in a manner similar to that reported during development. Although these early events were successful in producing morphologically normal-appearing regenerated fibres, complete maturation of many of these fibres was never achieved. Axonal distortion by neurofilaments, axonal degeneration and secondary demyelination were seen at 56 days following nerve transection. These changes progressed in severity with time as more axons advanced through the distal stump towards their peripheral target. Since regeneration occurs in the absence of endoneurial tubes, and because constrictive forces act on the nerve during regeneration, we suggest that these extrinsic factors limit the successful advancement of axons through the distal stump to their target organ.     

Quantitation of human serum polymeric IgA, IgA1 and IgA2 immunoglobulin by enzyme immunoassay

This report concerns the relative quantitation of serum polymeric IgA and polymeric IgA subclass concentrations by enzyme immunoassay (EIA). The assay relies on the specific binding of polymeric IgA to secretory component. Competition between pentameric IgM and polymeric IgA for binding to secretory component was observed. Thus, samples were adsorbed for IgM by affinity chromatography before the EIA was performed. The assay was used to determine an age-related range of serum polymeric IgA concentrations and to compare the polymeric IgA concentrations in patients with IgA nephropathy (n = 50) to those of controls (n = 50). The serum concentrations of both polymeric IgA and polymeric IgA1 increased with age reaching adult values of around 12 years of age. Polymeric IgA2 concentrations did not reach adult levels until 18 years of age. The ratio of the polymeric IgA concentration to the total serum IgA concentration was found to be significantly increased in children under 2 years of age compared with those over 4 years of age (Mann-Whitney U-test, P less than 0.01). Patients with IgA nephropathy had significantly increased concentrations of polymeric IgA (P = 0.001) and polymeric IgA1 (P = 0.001) but similar polymeric IgA2 concentrations to controls.     

C3 degradation products (C3d) in normal pregnancy.

Plasma C3 degradation products (C3d) were measured in 65 normal pregnancies and compared with those of non-pregnant women. No significant difference was detected between the two groups, although a difference had been previously reported. Plasma C3d estimations give an indication of complement activation and may be used as an indicator of disease activity in patients with systemic lupus erythematosus (SLE), irrespective of pregnancy.     

Introduction of Shigella flexneri 2a type and group antigen genes into oral typhoid vaccine strain Salmonella typhi Ty21a.

For protection against dysentery caused by Shigella flexneri 2a, an in vivo-constructed recombinant plasmid with genes specifying the S. flexneri type and group antigens located near the pro (min 6) and his (min 44) chromosomal markers, respectively, was made and transferred to the galE Salmonella typhi strain Ty21a. Strain Ty21a carrying this recombinant plasmid was shown by immunological and biochemical analyses to express the S. flexneri 2a type and group antigens. Mice immunized with this vaccine strain were found to be protected against challenge with virulent S. flexneri 2a, but not significantly against S. typhi challenge, presumably because synthesis of the Shigella antigens interfered with expression of the typhoid antigens. Elimination of the recombinant plasmid from Ty21a allowed this strain to again express typical S. typhi O antigens. Mouse protection against both S. typhi and S. flexneri 2a challenges was achieved with a whole-cell vaccine mixture composed of equal parts of Ty21a and the Ty21a-S. flexneri 2a hybrid strain.     

Efferent connections of the medial prefrontal cortex in the rabbit

The different cytoarchitectonic regions of the medial prefrontal cortex (mPFC) have recently been shown to play divergent roles in associative learning in rabbits. To determine if these subareas of the mPFC, including areas 24 (anterior cingulate cortex), 25 (infralimbic cortex), and 32 (prelimbic cortex) have differential efferent connections with other cortical and subcortical areas in the rabbit, anterograde and retrograde tracing experiments were performed using thePhaseolus vulgaris leukoagglutinin (PHA-L), and horseradish peroxidase (HRP) techniques. All three areas showed local dorsal-ventral projections into each of the other areas, and a contralateral projection to the homologous area on the other side of the brain. All three also revealed a trajectory through the striatum, resulting in heavy innervation of the caudate nucleus, the claustrum, and a lighter projection to the agranular insular cortex. The thalamic projections of areas 24 and 32 were similar, but not identical, with projections to the mediodorsal nucleus (MD) and all of the midline nuclei. However, the primary thalamic projections from area 25 were to the intralaminar and midline nuclei. All three areas also projected to the ventromedial and to a lesser extent to the ventral posterior thalamic nuclei. Projections were also observed in the lateral hypothalamus, in an area just lateral to the descending limb of the fornix. Amygdala projections from areas 32 and 24 were primarily to the lateral, basolateral and basomedial nuclei, but area 25 also projected to the central nucleus. All three areas also showed projections to the midbrain periaqueductal central gray, median raphe nucleus, ventral tegmental area, substantia nigra, locus coeruleus and pontine nuclei. However, only areas 24 and the more dorsal portions of area 32 projected to the superior colliculus. Area 25 and the ventral portions of area 32 also showed a bilateral projection to the parabrachial nuclei and dorsal and ventral medulla. The dorsal portions of area 32, and all of area 24 were, however, devoid of these projections. It is suggested that these differential projections are responsible for the diverse roles that the cytoarchitectonic subfields of the mPFC have been demonstrated to play in associative learning.